John Mears dot Co dot UK

Where 2 wrongs don't make a right, but 3 lefts do.


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Celestion Ditton
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Decca Valve Amp

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Sony MDP-850D Laserdisc Player.

This is my Sony MDP-850D Laserdisc Player.

Here are some photos of it.

 This was the the top of the range Sony unit back in 1994 and cost about 850.

Unit plays normal audio cds, cdv (cd video) and laserdiscs, both CAV (Constant Angular Velocity) and CLV (Constant Linear Velocity) differences detailed at bottom.

Plays both popular tv formats, UK PAL (Phase-Alternating Line) and NTSC (Never Twice the Same Colour) laserdiscs when used with a tv that supports both standards like JVC.

Has an auto reverse function, the laser assembly tracks its way round a "U" shaped track and plays the other side of the disc.

It supports analogue line out L / R via phono connections, Dolby Digital / AC3 via optical TOS link and coaxial digital.

Mic input with echo control for karaoke function.

2 / SCART sockets for connection to tv or video etc.

Constant Angular Velocity (CAV) or standard-play disc rotates at a constant 1500 RPM for a PAL disc and 1800 RPM for an NTSC disc. Each track, or path traced by the laser for a single rotation of the disc, produces a single frame. Each side of the disc holds up to 54,000 frames, the equivalent of 36 minutes of playback for a PAL disc and 30 minutes of playback for a NTSC disc. Each frame has a number that is stored with the data on the disc.

The Constant Linear Velocity (CLV) or extended-play disc doubles the maximum playing time to 60 minutes by varying the rotational speed from a maximum of 1500 RPM for a PAL disc and 1800 RPM for an NTSC disc to a minimum of 600 RPM as the laser beam moves away from the center of the disc. The disc surface therefore moves past the laser head at a constant rate, and each track is longer than it's predecessor.

I currently own 3 of these players, 2 100% workers and one faulty for spares, as I cannot get the chip needed to repair it anymore Doh!

Also own the official Sony factory test and repair manual with circuit diagrams, test points, typical voltage measurements hidden button press commands and spare parts list, I may run a copy off for a small fee if required.

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